1. Field of the Invention
This invention relates generally to a traffic signal device, and more particularly to such a device allowing the motorist to readily observe the time remaining for a traffic light change.
2. Description of the Prior Art
The standard electronically operated traffic signals in widespread use today alternatively display red and green lights for defining the intervals during which traffic may proceed or may not proceed. The drawbacks with the use of such signal devices include their failure to indicate the interval of time that a given light has before changing from red to green and from green to amber to red or from green directly to red. It is therefore impossible for both motorists and pedestrians to determine whether it would be safe, for example, to proceed even with the green light showing. Moreover, color blind persons cannot clearly discern between the red colored and the green colored traffic lights unless such lights are disposed in a particular location on the traffic signal device uniformly for the various intersections throughout the country. Otherwise, the words "Stop" and "Go" need to be imprinted on the respective red and green traffic lights themselves, or need to be mounted on some other portion of the traffic signal device.
U.S. Pat. No. 1,765,508 to SWAM discloses a traffic signal which recognizes the problem in the failure of standard traffic signals to indicate the interval of time that a red or green traffic light has to continue its signaling function. However, an altogether different approach is taken therein. A more cumbersome and complex device as compared of the invention is disclosed by requiring a reversal of movement of an endless conveyor having opaque plates thereon for gradually closing and opening a column through which lights are observed.